1. Field of the Invention
This invention relates to electric lamps and has particular reference to a photoflash lamp having an improved flash-ignition component.
2. Description of the Prior Art
Photoflash lamps which contain a filling of combustible fuel that is ignited by primer material that is disposed in a gap between the lead wires and subjected to a high voltage pulse are well known in the art. A photoflash lamp of this type having a pair of lead wires of unequal length that are held in spaced relationship by a side-vented glass sleeve that is anchored in the press seal of the envelope and surrounds the short lead wire and is terminated by a globule of primer material that covers the ends of both lead wires is disclosed in U.S. Pat. No. 3,873,260 issued Mar. 25, 1975 to Cote. A photoflash lamp that is fired in the same manner but contains a flash-ignition mount which includes a "donut-shaped" glass bead that joins the lead wires and is provided with a central opening that is filled with primer, and which optionally can also include a glass sleeve disposed around one of the lead wires below the bead to help prevent debris in the flashed lamp from shorting the lead wires, is disclosed in U.S. Pat. No. 3,884,615 issued May 20, 1975 to Sobieski.
A high-voltage type photoflash lamp having a flash-ignition mount that is similar to that shown in the aforementioned U.S. Pat. No. 3,873,260 but employs a glass sleeve which has no side vent opening and requires that the tip of the lead wire within the sleeve be melted so that it has a smooth rounded surface is disclosed in U.S. Pat. No. 4,008,040 issued Feb. 15, 1977 to Murray et al.
A photoflash lamp adapted to be ignited by applying a high-voltage pulse to primer material which bridges a pair of glass beads that enclose the lead wires and are supported by coatings of glass that surround the portions of the lead wires below the beads is disclosed in U.S. Pat. No. 3,501,254 to Nijland et al.
A photoflash lamp that is fired by passing an electric current through a filament supported by a mount structure which includes a glass bead that holds the lead wires in place and is provided by glass sheathes which enclose the lower portions of the lead wires to prevent after-flash shorting of the wires is described in U.S. Pat. No. 3,959,860 issued June 1, 1976 to Schindler. A similar type lamp which contains a flash-ignition mount having a non-shorting feature is shown in U.S. Pat. No. 3,816,054 issued June 11, 1974 to Baldrige, Jr. et al. The mount consists of a bead that joins the lead wires and has a glass sleeve that is located on top of the bead and encloses the upper extremity one of lead wires below the point at which it is joined to the primer-coated filament which is energized to fire the lamp. The use of a glass bead having a "stretched" or elongated upper surface that extends toward the primer-coated filament and thus prevents post-ignition short circuiting of the wires is disclosed in U.S. Pat. No. 3,919,750 issued Nov. 18, 1975 to Saunders et al.